Had to double take at reading Robert Morriss (surely no relation..surely)

> Beale entrusted a box containing the encrypted messages to a local innkeeper named Robert Morriss

If it's just an unknown one time pad we're looking for, this is pretty damning:

> If the Declaration of Independence is used as a key for the first cipher, it yields alphabetical sequences such as abfdefghiijklmmnohpp and others